Transient edema is an inevitable reaction, and it is considered that up to a third of tattooed individuals may experience this minor complication.23 It manifests as induration of the tattooed area and may or may not be accompanied by pruritus, disorders in skin pigmentation, and focal dermal hemorrhagic disorders, among others, which self-resolve within a period of 2 to 3 weeks after pigment injection. These manifestations may result from the trauma of hundreds of needle punctures, irritation from alcohol use, or an acute inflammatory reaction to the ink and/or diluent, leading to disruption of the epidermal basal membrane and some necrosis of dermal and epidermal cells.24,25

Allergic contact dermatitis is characterized by eczematous, hyperkeratotic, or ulcer-necrotic lesions in the tattooed area, which may be photosensitized due to alteration of pigments through Ultraviolet (UV) decomposition or haptenization of antigens. Haptenization occurs when UV light affects the pigments and alters their chemical composition, making them recognizable as foreign substances and triggering an immune response. This can result in erythematous, vesicular, or exfoliative eruptions.26 Despite the transition to azoic-based inks, hypersensitivity reactions in tattoos are still primarily attributed to the presence of mercury in red inks.16,27 Regarding other ink colors, confirming the responsible allergen is difficult to achieve through patch testing due to the lack of precise lists of ingredients and comparable allergens for testing, and the results are often negative.28 This reinforces the idea that ink haptenization is a necessary step in the pathogenesis of adverse reactions.28 It is important to note that the main differential diagnosis for this reaction is pseudolymphoma, which often affects more than one color of the tattoo.16

Tattoos can trigger the appearance of new lesions in individuals with preexisting dermatoses. These lesions typically appear a few days to weeks after the tattoo, although they can also extend for several months.29 Chronic skin diseases such as psoriasis, vitiligo, granuloma annulare, lichen planus, lichen sclerosus, pyoderma gangrenosum, lupus erythematosus, morphea, and Darier's disease share a common characteristic: cutaneous manifestations can be reproduced in areas of focal trauma (Koebner's isomorphic phenomenon).5,27 Patients with atopic dermatitis may develop contact allergy and photosensitivity reactions that trigger eczematous reactions or worsen exacerbations.27 Similarly, patients with preexisting pyoderma gangrenosum have been reported to develop ulcers resembling this condition at the tattoo site, especially in the lower extremities, due to the pathergy phenomenon.30,31 It is important to consider the recommendation that patients with preexisting dermatoses abstain from getting tattoos or be evaluated by a dermatologist before doing so, due to the potential risk of exacerbating the underlying pathology.

These occur months or years after the tattoo and are primarily associated with foreign body-type reactions, with approximately 29.3% of cases being associated with cutaneous or systemic sarcoidosis (Fig. 1). Granulomatous skin reactions associated with tattoos can be an initial presentation of a systemic disease like sarcoidosis, requiring additional studies such as chest radiography or computed tomography and laboratory tests.32 The mechanism of sarcoidosis induction in individuals with tattoos could be pigment overload, which can occur at the edges or corners of a tattoo where pigment density is higher than in other areas, or in cases where there is repeated introduction of foreign material. This could lead to chronic immune system exposure to tattoo ink, resulting in sustained foreign body-type granulomatous inflammation and subsequent development of focal autoimmunity in genetically susceptible individuals for sarcoidosis development. This explains the often-prolonged latency period between tattoo placement and the appearance of clinical symptoms.33,34 Sarcoidosis has been detected in tattoos of patients who have been treated with interferon for any reason. For this reason, it is suggested that individuals with a history of sarcoidosis avoid tattooing if they are being treated with interferon. Asymptomatic or pruritic indurated erythematous-violet papules and nodules on the tattooed area (Fig. 2) can also occur secondary to lichen planus, pseudolymphomas, lymphomatoid papulosis, lymphomas, among others, with the diagnosis confirmed through histopathology.35

Figure 1.

Papulonodular lesions following cosmetic eyebrow tattooing. The final diagnosis was sarcoidosis. Photographic archive of the Dermatology Service at the University of Antioquia.

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Figure 2.

Papulonodular lesions over a black and red tattoo in the lower lumbar region. The histopathological diagnosis was pseudolymphoma. Photographic archive of the Dermatology Service at the University of Antioquia.

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The relationship is not clear; however, isolated cases of hypersensitivity vasculitis have been reported. It is important to rule out other causes of vasculitis such as infection, medications, malignancy, or systemic diseases.36

It is the most common hypersensitivity tissue reaction that can occur in response to any ink color, but with a predilection for red ink due to the presence of components such as nickel, mercury, and cadmium, presenting even as verrucous lesions.37 Lichenoid reactions can be caused by lichen planus or overlap with allergic reactions, and sometimes it is difficult to distinguish between these two etiologies, making clinical correlation crucial. Sometimes the lichenoid inflammatory pattern is associated with the Koebner isomorphic phenomenon in patients with undiagnosed lichen planus, so when it is found, other anatomical sites should be examined.38,39 Histopathologically, it is characterized by a band-like lymphocytic dermal inflammatory infiltrate with interface changes, basal vacuolar degeneration, and dyskeratotic keratinocytes40 (Fig. 3).

Figure 3.

Lichenoid pattern. Epidermal hyperplasia, orthokeratosis, Malpighian layer with spongiosis and scattered dyskeratocytes. Vacuolar damage of the basal layer. In the dermis, there is an inflammatory infiltrate in a band-like pattern with some cytoid bodies containing black pigment, (Hematoxylin & eosin, [A] ×100, [B] ×400). Photographic archive of the Dermatopathology Laboratory, Dermatology Section, University of Antioquia.

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This reaction can be found in the acute presentation following the tattoo (transient edema) or can be the manifestation of an allergic response. Histopathologically, it is characterized by intercellular epidermal edema (eczema) accompanied by a mixed or non-mixed chronic lymphocytic dermal inflammatory infiltrate, which can overlap with the lichenoid pattern 41,42 (Fig. 4).

Figure 4.

Spongiotic dermatitis. Preserved thickness of the epidermis with marked spongiosis and some dyskeratocytes. Basal vacuolar damage. Black ink pigment is identified in the dermis, (Hematoxylin & eosin, [A] ×100, [B] ×400). Photographic archive of the Dermatopathology Laboratory, Dermatology Section, University of Antioquia.

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An inflammatory infiltrate composed of epithelioid histiocytes, multinucleated giant cells with variable lymphocytic and polymorphonuclear infiltrate, which can organize into different patterns, of which foreign body granuloma and sarcoidal granuloma are the most common. Foreign body granulomas are characterized by pigment-laden foreign body-type giant cells. Sarcoidosis is defined by non-caseating epithelioid granulomas with little or no accompanying inflammatory response43 (Fig. 5). Staining and/or cultures should be performed to rule out fungal or mycobacterial infection. Granulomas with central necrosis (tuberculoid) are mainly observed in tuberculosis and leprosy, although they have also been described in response to ferric oxide and chromium salts in cosmetic tattoos. Granuloma annulare and necrobiosis lipoidica-like reactions are rarer.16,27,38 In one described case, a disease similar to Rosai-Dorfman was observed with a dense lymphocytic and histiocytic inflammatory infiltrate in the dermis. Abundant histiocytes with emperipolesis of inflammatory cells were found. However, unlike Rosai-Dorfman disease, there was no involvement of lymph nodes, which is a characteristic finding of that disease.44

Figure 5.

Granulomatous inflammation of a sarcoid type. (A) Papulonodular lesions in a tattoo on the right scapular region. (B) Granulomatous infiltrate of sarcoid type associated with black ink pigment (Hematoxylin & eosin, ×400). Systemic studies revealed sarcoidosis. Photographic archive of the Dermatopathology Laboratory, Dermatology Section, University of Antioquia.

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Pseudolymphoma is a clinically benign reaction characterized histopathologically by dense nodular dermal lymphocytic infiltrates or band-like lichenoid infiltrates. Immunohistochemical studies may show the presence of B- and T-cells with a normal immunophenotype, and gene rearrangement studies will reveal polyclonal lymphocyte populations.45 The pathogenesis is uncertain; however, it has been reported to occur frequently in areas of tattoos with red ink, which induces chronic antigenic stimulation resulting in polyclonal proliferation of B- and T-lymphoid cells. Although malignant transformation is rare, cases of B-cell lymphomas associated with tattoos have been described, so close follow-up is recommended. The differential diagnosis includes allergic reactions, B-cell and T-cell lymphomas, lymphomatoid papulosis, and infections.46,47

It is a reactive pattern characterized by marked epidermal hyperplasia accompanied by follicular hyperkeratosis and variable dermal inflammation composed of lymphocytes and plasma cells.48 It can be triggered by stimuli such as chronic irritation, scarring, trauma, and nonspecific inflammatory or infectious dermatoses, presenting between 2 weeks to 3 months after tattooing and should be differentiated from neoplastic entities such as keratoacanthoma and squamous cell carcinoma.49

Characterized by dermal sclerosis and/or dermal fibrosis, which can be secondary to an underlying connective tissue disease or represent the development of dermal fibrosis in a setting of chronic inflammation or hypersensitivity50 (Fig. 6).

Figure 6.

Sclerodermiform/morphea-like pattern. The epidermis appears unaltered in thickness. In the dermis, fibrosis with effacement of cutaneous appendages is observed, associated with deposition of black ink pigment, (Hematoxylin & eosin, [A] ×100, [B] ×400). Photographic archive of the Dermatopathology Laboratory, Dermatology Section, University of Antioquia.

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Other described histopathological patterns include psoriasiform, vasculitic, and neutrophilic dermatosis.

Bacterial infectious complications have been estimated to affect 1%‒5% of tattooed individuals.14 The most frequently reported ones include impetigo, folliculitis,52 furunculosis, abscesses, ecthyma, cellulitis, erysipelas, and gangrene, with the main causative agents being Staphylococcus aureus, Streptococcus pyogenes, Clostridium difficile, and Pseudomonas aeruginosa.53 Clinical manifestations typically appear within days to a few weeks after getting the tattoo and may include local pain, erythema, edema, fever, and, in some cases, purulent discharge. Some studies have reported that up to 28% of tattoo ink bottles are improperly sealed, and 10% may be contaminated with both pathogenic and non-pathogenic bacteria, posing a significant risk of adverse reactions to this practice.54 Transmission of syphilis through tattoos is anecdotal and was described in the past because of contamination with saliva from syphilitic tattoo artists. There have also been reported cases of secondary syphilis in tattooed areas, although these are currently rare.55,56 Generally, bacterial infections are easily treatable, and the treatment does not significantly differ from that of other infectious conditions.16

Non-tuberculous mycobacteria are ubiquitous in water and can infect tattoo inks when gray ink is prepared by diluting black ink with non-sterile or non-distilled tap water. Additionally, ink dilution reduces the antimicrobial efficacy of any preservatives that may be present.57 The most frequently isolated mycobacteria include Mycobacterium chelonae, Mycobacterium haemophilum, Mycobacterium abscessus, Mycobacterium immunogenum, Mycobacterium massiliense, and Mycobacterium fortuitum.58 Clinically, papules, pustules, or ulcerated nodules limited to the tattooed area may be observed.59

In areas where leprosy is endemic, cutaneous inoculation with Mycobacterium leprae can occur, and manifestations may appear decades after the inoculation.60 In 2002, Ghorpade et al. described 31 cases of leprosy inoculated through tattoos and established the following diagnostic criteria: 1) Appearance of the first leprosy lesion after the tattoo, on the same site; 2) Presence of a single leprosy lesion on a single tattoo mark; 3) Histopathological evidence of leprosy and dermal tattoo pigment; 4) Absence of any pre-existing skin disease before the tattoo; 5) Demonstration of M. leprae in the tattoo instrument through smears or inoculation in the footpad of a mouse, if possible.60

Infections by Mycobacterium tuberculosis or Mycobacterium bovis have also been reported after tattooing, with clinical manifestations appearing 2–4 weeks after inoculation. They are characterized by the formation of papules or erythematous nodules that progress to superficial ulcers (tuberculous chancre), accompanied by painless regional lymphadenopathy. In immunocompromised patients, progression to lupus vulgaris and tuberculosis cutis verrucosa, or even hematogenous dissemination, may occur.6,61

These infections should be considered when patients present with skin reactions decades after getting a tattoo or in patients who have been tattooed in prison or in environments where sterile techniques are not employed. Diagnostic tests include biopsy, tissue culture, and PCR for mycobacteria. Special stains for mycobacteria in biopsies are useful when positive but are not sufficient to rule out an infection. The tuberculin skin test also has great diagnostic value.16,27

Some viral infections can be transmitted through contaminated instruments and inks used during tattooing. The most described ones include HIV, Hepatitis B (HBV), and Hepatitis C (HCV), although the risk of transmission under optimal biosafety conditions is very low.5,62 There have been reports of warts appearing at tattoo sites, with some cases being triggered by intense sunburn. It was postulated that local immunosuppression induced by UV radiation may reactivate the Human Papillomavirus (HPV). Therefore, a reasonable recommendation is to protect freshly tattooed skin from UV exposure.27,63 The most common serotypes of HPV are 3, 10, 27, 28, 47, and 49.23 Infection by the molluscum contagiosum virus may occur weeks or months after tattooing, and when it becomes widespread, it can happen in the context of an HIV infection.27 Herpes simplex virus type 1 can cause primary infection during the procedure or during the healing phase. In patients with a history of HSV-1 infection, it can reactivate, known as “herpes compunctorum”. 64 Other viral infections possibly related to tattooing are molluscum contagiosum, rubella, and vaccinia. It should be noted that several of these infectious conditions are declining due to vaccination practices in early life stages and the increased use of aseptic techniques that mitigate the risk of viral transmission. 5,65

Cutaneous fungal infections in tattooed areas are very rare, although some cases of ringworm, pityriasis versicolor, candidiasis, sporotrichosis, aspergillosis, zygomycosis, or Acremonium infections have been described.27,59 Superficial mycoses can occur during the tattoo healing process, with the main etiological agent being Microsporum canis, a dermatophyte isolated from the hair of domestic animals.23

These are extremely rare. Some cases of cutaneous leishmaniasis have been reported after tattoos in individuals with visceral leishmaniasis or HIV.27

Pain and intense itching can occur after a tattoo and have been associated with possible involvement of cutaneous nerve branches, especially C fibers of sensory nerves. 77

Cutaneous complications during Magnetic Resonance Imaging (MRI)

During MRI scans, cutaneous manifestations can occur in the tattooed area, such as skin irritation, edema, and burning sensation. This could be caused by zinc oxide present in tattoo inks or by metals with ferromagnetic properties capable of conducting currents and heating adjacent tissues. 78,79 Additionally, the metallic pigments in the inks can interfere with the quality of the MRI and cause artifacts in the image. It should be emphasized that tattoos are not a contraindication for undergoing MRI. 16

Reactions related to sunlight exposure have been found in up to 20% of cases. 80 Clinically, they manifest as erythematous and edematous lesions, primarily described in tattoos containing cadmium sulfide, which is usually present in traditional yellow and red pigments. 6 The mechanism is believed to involve the induction of reactive species that interact with DNA, proteins, or lipids, compromising their normal function and mediating symptoms such as pain, itching, or cell death. 81